Garage door opener

ABSTRACT

A mechanism for operating a door including a reversible electric motor, a rotatable shaft connected therewith, with the shaft having a given rotational speed, a worm having a bore extending the entire length thereof, with the shaft being slidably received therein, key means provided in said bore for locking the shaft into rotational engagement with the worm, a worm gear in working engagement with the worm, a worm gear in working engagement with the worm and having a given rotational speed proportioned to the rotational speed of the shaft, door closure actuating means operatively connected with the worm gear, limit switch means electrically connected to the motor and disposed in a region adjacent the worm, and switch actuating means mounted on the worm and contacting the limit switch means when the rotational speed of the worm gear varies from the given rotational speed of the worm.

I United States Patent Primary Examiner-J. Karl Bell ABSTRACT: Amechanism for operating a door including a reversible electric motor, arotatable shaft connected therewith, with the shaft having a givenrotational speed, a worm having a bore extending the entire lengththereof, with the shaft being slidably received therein, key meansprovided in said bore for locking the shaft into rotational engagementwith the worm, a worm gear in working engagement with the worm, a wormgear in working engagement with the worm and having a given rotationalspeed proportioned to the rotational speed of the shaft, door closureactuating means operatively connected with the worm gear, limit switchmeans electrically connected to the motor and disposed in a regionadjacent the worm, and switch actuating means mounted on the worm andcontacting the limit switch means when the rotational speed of the wormgear varies from the given rotational speed of the worm.

MOTOR- SWITCH RELAY WORM WORM- GEAR T'BAR WIRE CABLE ass-3.313

PATENTED JAN] 1 I972 LUCIEN LAFONTAINE GARAGE noon OPENER This inventionrelates to a mechanical way to actuate a limit switch or switches forstopping an electric motor or reversing its polarity in garage dooroperators and to the use of a drum instead of a pulley to avoid slippageof the wire cable when used instead of a roller chain.

Further details of the invention will become apparent from theaccompanying single sheet of drawing and from the following descriptionand claims.

FIG. 1 represents an ordinary garage door operator.

FIG. 2 represents the disposition of the worm on the shaft of the motorwith arrangement of the springs, the spacers with limit fingers and thebearings.

FIG. 3 represents the worm driving the worm gear which in turn drivesthe drum.

On the shaft of the electric motor (FIG. 2) there are a worm A, twosprings B, two bushings or bearings C, two spacers with limit fingers D,or a worm, one spring, one bushing or bearing, one spacer with limitfinger(s).

The worm follows the rotation of the motor by the use of a key (FIG. 3)inserted in the keyway of the shaft and the worm, or by a flat on theshaft of the motor and a corresponding flat in the hole of the worm.

When the motor starts turning in one direction the worm drives the wormgear (FIG. 2) F which in turn drives a chain sprocket or a pulley or adrum (FIG. 1 & 3) E.

The chain sprocket or the pulley or the drum drives a roller chain or awire cable attached to both ends of the carriage that slides on the Uchannel or T bar, the said carriage being attached indirectly to thedoor by an arm (FIG. 1).

When the door is fully opened or fully closed or if the door, in its waydown or up, encounters an obstacle or if the door does not operateproperly, the speed of the worm gear reduces or the worm gear stopscompletely.

As the motor continues turning at its normal speed the worm will thenslide on the shaft of the motor pushing the limit finger(s) (FIG. 2D)that actuates the fixed or adjustable limit switch(es) (FIG. 2G) thatstops the motor or reverses the rotations of the motor if the limitswitch is connected to a relay (reversing contactor) that reverses thepolarity of the motor.

Therefore the mechanical way as claimed and described above to actuate alimit switch(es) to stop the motor or reverse its polarity residesessentially in the fact that the worm instead of being firmly secured onthe shaft of the motor slides back and forth on the said shaft and iskept in normal position by the spring(s) that will deflect underpressure of the worm allowing the limit finger( s) on the spacer(s) toactuate a limit switch(es) that stop the motor or reverse its polaritythrough a reversing contactor. The bushing(s) or bearing(s) (FIG. 2C)are used to avoid friction between the worm and the spacer(s).

A further object of the invention is to avoid the slippage of a wirecable, when used instead of a roller chain, by using a drum instead of apulley, on which drum the wire cable is enrolled or firmly secured, andon which drum one length of the wire cable attached to one end of thecarriage of the operator rolls itself while the other length of the wirecable attached to the other end of the carriage unrolls itself at thesame time (FIG. I-2-3-E).

Although a specific embodiment of the invention has just been describedit will be understood that various modifications may be made theretowithout departing from the invention the scope of which is only to beconstrued from the appended claims.

Iclaim:

l. A mechanism for operating a door comprising, in combination, areversible electric motor; a rotatable shaft connected therewith andbeing driven thereby, said shaft having a given rotational speed; a wormhaving a bore extending the entire length thereof, said shaft beingslidably received in said bore; key means provided in said bore lockingsaid shaft into rotational engagement with said worm but allowinglongitudinal movement of said worm on said shaft; a worm gear in workingengagement with said worm, said worm gear having a given rotationalspeed proportioned to the rotational speed of said shaft, door closureactuating means operatively connected to said worm gear; a pair of limitswitch means electrically connected to said motor and each oppositelydisposed in a region adjacent to the extremities of said worm, said pairof limit switch means including a first limit switch for stopping saidmotor from rotating said shaft and a second limit switch for causingsaid motor to reverse the rotation of said shaft; a pair of switchactuating means each mounted at one extremity of said worm and includinga first finger for contacting said first limit switch and a secondfinger for contacting said second limit switch; and a pair of springmeans axially mounted on said motor shaft and disposed thereon on eachside of said switch actuating means maintaining said worm in a normalposition in relation to said worm gear; said worm being longitudinallyslidable on said shaft when the rotational speed of said worm gearvaries from the rotational speed of said worm whereby said pair ofspring means cause said first finger to contact said first limit switchto stop the rotation of said shaft when the worm slides longitudinallyin one direction on said shaft and cause said second finger to contactsaid second limit switch to reverse the rotation of said shaft when theworm slides longitudinally in the other direction on said shaft.

2. A mechanism as defined in claim 1 wherein said door closure actuatingmeans include a drum and a wire cable enrolled on said drum.

1. A mechanism for operating a door comprising, in combination, areversible electric motor; a rotatable shaft connected therewith andbeing driven thereby, said shaft having a given rotational speed; a wormhaving a bore extending the entire length thereof, said shaft beingslidably received in said bore; key means provided in said bore lockingsaid shaft into rotational engagement with said worm but allowinglongitudinal movement of said worm on said shaft; a worm gear in workingengagement with said worm, said worm gear having a given rotationalspeed proportioned to the rotational speed of said shaft, door closureactuating means operatively connected to said worm gear; a pair of limitswitch means electrically connected to said motor and each oppositelydisposed in a region adjacent to the extremities of said worm, said pairof limit switch means including a first limit switch for stopping saidmotor from rotating said shaft and a second limit switch for causingsaid motor to reverse the rotation of said shaft; a pair of switchactuating means each mounted at one extremity of said worm and includinga first finger for contacting said first limit switch and a secondfinger for contacting said second limit switch; and a pair of springmeans axially mounted on said motor shaft and disposed thereon on eachside of said switch actuating means maintaining said worm in a normalposition in relation to said worm gear; said worm being longitudinallyslidable on said shaft when the rotational speed of said worm gearvaries from the rotational speed of said worm whereby said pair ofspring means cause said first finger to contact said first limit switchto stop the rotation of said shaft when the worm slides longitudinallyin one direction on said shaft and cause said second finger to contactsaid second limit switch to reverse the rotation of said shaft when theworm slides longitudinally in the other direction on said shaft.
 2. Amechanism as defined in claim 1 wherein said door closure actuatingmeans include a drum and a wire cable enrolled on said drum.